How do I rotate my Camera around my sphere using the arrow keys?

My code is currently this, also it's not much however please add onto it. public GameObject playerpos; private float distancey = 3.0f; private float distancex = -4.0f; void Update() { transform.position = new Vector3(playerpos.transform.position.x + distancex, playerpos.transform.position.y + distancey, playerpos.transform.position.z); }